How Meal Timing Affects Your Health

It’s not just what you eat that matters – when you eat also impacts your health!

The foods we choose to consume undoubtedly have a significant impact on our health. However, few laypeople (or health professionals, for that matter) give much thought to the effect of meal timing on our health. Interestingly, a rapidly growing body of research indicates that when we eat may be just as important as what we eat for building resilient long-term health. Read on to learn about several important aspects of meal timing and how fine-tuning your meal timing can support your health.

What’s Wrong with Eating Many Small Meals Throughout the Day?

A common question I get from clients is whether they should eat smaller, more frequent meals throughout the day. This recommendation has been floating around the health and wellness sphere for several decades, thanks in part to early epidemiological research that suggested an increased meal frequency (i.e., eating many small meals throughout the day) could lower concentrations of total cholesterol and LDL cholesterol and reduce the risk of obesity. (1, 2) However, in the research reporting an inverse association between increased meal frequency and obesity, underreporting of caloric intake was identified as a potential confounding variable; the researchers attempted to control for this confounder, but residual confounding is possible. Furthermore, the reduced reported meal frequency in these studies could be due to aberrant, unhealthy eating patterns such as skipping meals (like breakfast and lunch) and then gorging on food in the evening, an eating pattern associated with poor metabolic health.

Unfortunately, the mainstream media (and some ill-informed health professionals) still advise individuals to consume 5-6 meals per day, typically, as three main meals and two snacks, to support “appetite control” or “blood sugar control.” However, the reality is that eating at this frequency is evolutionarily unprecedented and creates a vicious cycle of blood glucose fluctuations that may actually trigger food cravings and exacerbate poor blood sugar control.

Every time you eat food that contains some carbohydrate (and to a lesser extent, protein), your body releases a hormone called insulin. Insulin’s role is to shuttle glucose in the blood derived from the carbohydrates you consumed into your cells, where the glucose can be used for cellular energy production. While insulin release after eating is an entirely normal process, frequent blood glucose excursions (fluctuations in blood glucose) caused by frequent eating provoke oxidative stress and inflammation, two factors linked to virtually every chronic disease we face today. With this information in hand,it follows that reducing our meal frequency, and thus our blood glucose excursions, may be ideal for our health.

On the contrary, prospective research indicates that higher meal frequencies (i.e., consuming six or more meals consumed per day) are associated with an increased risk of chronic diseases. In contrast, lower meal frequencies (2-3 meals per day) are associated with a reduced risk of chronic diseases. (3)

There are a few exceptions to the “avoid frequent eating” rule; people who are underweight and need to gain weight, those recovering from eating disorders, and pregnant women may need to eat more frequently to support their health.

What About Grazing?

I have more than a few clients who are self-reported “grazers,” meaning they prefer to grab a bit of food here and there throughout the day rather than sit down to eat balanced meals. Along the same lines as what I’ve mentioned above, the frequent food consumption intrinsic to grazing behavior results in frequent blood sugar fluctuations that may compromise one’s health. Implementing a regular meal schedule with 2-3 meals per day and one snack per day, if needed, may promote healthier blood glucose homeostasis.

Key Takeaways:

  • Avoid eating more than 3-4 meals per day.

  • Avoid grazing; try to establish consistent mealtimes instead.

Distribution of Daily Energy (Calorie) Intake

Research indicates that humans’ basal metabolic rate (BMR), or the body’s energy expenditure used to fuel essential body functions at rest, is higher in the morning than in the evening. Insulin sensitivity is also higher in the morning. (4) These findings suggest that “front-loading” more of your caloric intake at the beginning of the day, instead of eating more food at night, may be ideal for promoting metabolic health.

Early time-restricted eating (eTRE), an eating strategy that involves eating the last meal of one’s day by early afternoon (4 pm is a typical cutoff for eTRE) and then fasting until breakfast the next day, is one example of a meal schedule that capitalizes on the body’s increased BMR and insulin sensitivity early in the day. eTRE has been found to reduce appetite and increase the body’s ability to burn fat. (5) However, it is important to note that early TRE is a departure from the cultural norm regarding meal timing, so it is not a feasible approach for many people.

Key Takeaways:

  • Try to eat your heaviest meal for breakfast and your lightest meal at dinner since your metabolism is most efficient earlier in the day.

  • Consider early time-restricted eating, particularly if you struggle with significant blood sugar dysregulation.

Fasting

Fasting represents another temporal modification of food intake that may support our optimal health. Fasting is defined as an “… abstention from food and caloric beverages for a specific interval of time, usually longer than the normal 8 h of sleep.” (6) There are numerous ways to fast; early time-restricted eating, mentioned above, is just one example. Another approach is to restrict your eating window to 8-10 hours each day and fast for 14-16 hours overnight. This approach works well for many people and offers significant health benefits, even if not implemented as eTRE. Multi-day fasting is another approach to fasting that I will reserve for a separate article since it requires extensive attention.

Fasting, in the form of time-restricted eating, is associated with multiple health benefits, including:

  • Improved mitochondrial function; your mitochondria are the energy powerhouses of your cells, so enhancing their function improves energy generation (7)

  • Improved glycemic control (8)

  • Reduced inflammation (9)

  • Improved synchronicity of the circadian clock (more on this below) (10)

Time-restricted eating is a simple, actionable way to access the health benefits of optimal meal timing. I frequently recommend that my clients start with a 14:10 approach, whereby they fast for 14 hours overnight and eat during a 10-hour time window each day. However, there is no one-size-fits-all approach to TRE; a clinical nutritionist can help you discern the optimal fasting schedule for your needs. This is something I frequently address with clients in my private practice.

Key Takeaways:

  • Consider restricting your “eating window” to an 8-10 hour period of time each day.

  • Aim to fast for 14-16 hours overnight, between dinner and breakfast the next day.

Nighttime Eating

Nighttime eating is a relatively novel behavior from an evolutionary perspective. Before the invention of the lightbulb, which suddenly allowed humans to stay up far past sundown, humans lived according to the natural cycle of light and dark and concluded most of their daily activities, including eating, by the time darkness settled in. Therefore, eating at night does not necessarily jive with our biology; indeed, research indicates that eating at night throws off our circadian rhythms, with significant health implications.

What exactly is your circadian rhythm, and why does eating at night disrupt it? Your circadian rhythm is the internal set of biochemical processes that regulates many aspects of your physiology, including your sleep cycle and energy expenditure. Your body contains “clocks,” collections of proteins and other signaling molecules, distributed throughout your tissues that regulate your circadian rhythm. While these clocks are primarily impacted by light and dark, food intake also affects circadian clock activity. By providing our bodies with nutrient “cues” in the form of food during the dark cycle, we essentially desynchronize our circadian clocks. (11) Conversely, when we eat during daylight hours, on a regular schedule (regularity of food intake synchronizes circadian clocks), and avoid consuming meals close to bedtime, we can improve our circadian rhythmicity. Improved circadian rhythmicity, in turn, leads to improvements in numerous downstream functions, including inflammation regulation, blood sugar control, and brain function.

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“Unusual feeding times may result in alterations to total energy expenditure (TEE), dysregulation of feeding behaviours, changes in appetite stimulating hormones and glucose metabolism”

— Shaw E et al. The Impact of Time of Day on Energy Expenditure: Implications for Long-Term Energy Balance. 2019; 11(10): 2383.

It is also important to avoid eating close to bedtime, as this will cause your body to prioritize digestion during sleep rather than other reparative processes. I recommend that my clients try to wrap up their last meal of the day at least three hours before bed. Please note that some people will not do well with this approach and may need a bedtime snack; there are several reasons people may need a bedtime snack, so I will reserve this topic for a separate blog.

Key Takeaways:

  • Try to eat most of your meals during daylight hours.

  • Try to wrap up your last meal of the day at least three hours before bed.

Timing of Macronutrient Consumption Within a Meal

Surprisingly enough, the times at which you eat different macronutrients (protein, carbohydrate, and fat) in a given meal may also impact your health! Research indicates that eating non-starchy vegetables or protein first and second, and carbohydrates last attenuate the postprandial blood sugar response. (12) Eating these foods before carbohydrates attenuate the postprandial (post-meal) blood sugar response by providing fiber (from the vegetables), which slows down glucose absorption in the gut, and through the insulin and GLP-1 augmenting effects of dietary protein ingestion. (13)

Key Takeaways:

  • Eat your non-starchy vegetables and proteins first in your meals, and carbohydrates last, to support healthy blood sugar control.

The foods you choose to eat undoubtedly have a significant influence on your health. However, I hope this article has made it clear that meal timing is equally important! I hope this article has clarified some aspects of meal timing that you can put into practice in your life.

Are you struggling with gut issues or weight loss resistance? Optimizing your meal timing can dramatically improve these health concerns. Not sure where to start with changing up your meal timing? Consider working with me! I am currently accepting new clients in my clinical nutrition practice. If you’re interested in diving deep into improving your health by working one-on-one with me, reach out to me here to schedule your discovery call. The discovery call will allow us to meet and talk together to decide if my nutrition services are the right fit for your needs. I look forward to connecting with you!

1 thought on “How Meal Timing Affects Your Health”

  1. I am confused and having trouble figuring out how to eat. I have MCAS and mold toxicity and very high anxiety that has been difficult to balance.
    I just was introduced to the concept that: small, frequent meals of protein and carbs reduce the adrenaline that triggers anxiety.
    Complete opposite to your article here but your article also makes total sense.
    Help!

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